Can't generate lighting...

On the Halo 2 Anniversary forge I ran into an issue. The map was doing fine until my friend lagged out. Thinking this was a glitch he rejoined. When I loaded in the map was all black. Going into forge and out again the lighting worked but for my friend he said it would finish generating lighting and go back to generating lighting once done. After the lighting glitch stopped his Xbox One crashed and he could no longer join or play on the map. My other friend could but I had finished the map, so we tested it on race and the lighting kept regenerating and he crashed. If anyone has a solution please inform me of how to fix it. Thanks -Viper